import tables
let 
  OrbitalPeriods = toTable {
     "Mercury": 0.2408467,
     "Venus": 0.61519726,
     "Earth": 1.0,
     "Mars": 1.8808158,
     "Jupiter": 11.862615,
     "Saturn": 29.447498,
     "Uranus": 84.016846,
     "Neptune": 164.79132,
  }
  SecondsPerYear = 31557600.0
proc age*(planet: string, age: int64): float = 
  float(age) / SecondsPerYear / OrbitalPeriods[planet]